Higher integration of semiconductor devices have increased the importance to control pattern on the outermost face as well as to perform alignment control (shape control) of an upper-layer pattern and a lower-layer pattern and dimension control of a hole opening. A scanning electron microscope (hereinafter called a SEM) has been used typically for the shape control and the dimension control of such a multilayered device (three-dimensional device).
Patent Literature 1 discloses a SEM provided with an energy filter capable of selecting signal electrons detected according to their energies. This type of SEM adjusts a threshold voltage of the energy filter, whereby a contrast image corresponding to a difference in surface potential of the device can be obtained.
Patent Literature 2 discloses a SEM including a detector for back scattered electrons and a detector for secondary electrons mounted thereon.